Fix a bug in splitting line on S3 file with DD_MULTILINE_LOG_REGEX_PATTERN

[showwin]

What does this PR do?

Fix a parsing issue for a S3 file with DD_MULTILINE_LOG_REGEX_PATTERN environment variable, which is introduced by the refactoring at 196c633

Motivation

My log files in S3 bucket was parsed wrongly and ingested to Datadog Log when I upgraded the version from 3.108.0 to 3.116.0. Strictly speaking, the issue was introduced from 3.113.0 [diff].

Testing Guidelines

Since this is a very small change, I didn't wrote any test code. Instead, I paste the sample code here for easier understanding

In [1]: data = 'hello\r\nnext line\nbye'

# expected
In [2]: for line in data.splitlines():
    ...:     print(line)
    ...:
hello
next line
bye

# Now. My parsed log in Datadog Log is like this now.
In [3]: for line in data:
    ...:     print(line)
    ...:
h
e
l
l
o



n
e
x
t

l
i
n
e


b
y
e

Additional Notes

This problem happens only when DD_MULTILINE_LOG_REGEX_PATTERN is given but the content of file doesn't match it.

Types of changes

• Bug fix
• New feature
• Breaking change
• Misc (docs, refactoring, dependency upgrade, etc.)

Check all that apply

• This PR's description is comprehensive
• This PR contains breaking changes that are documented in the description
• This PR introduces new APIs or parameters that are documented and unlikely to change in the foreseeable future
• This PR impacts documentation, and it has been updated (or a ticket has been logged)
• This PR's changes are covered by the automated tests
• This PR collects user input/sensitive content into Datadog
• This PR passes the integration tests (ask a Datadog member to run the tests)
• This PR passes the unit tests
• This PR passes the installation tests (ask a Datadog member to run the tests)

[showwin]

Even though the log says "splitting by line", the self.data_store.data is not split by line for now, actually.

[ViBiOh]

Nice catch, beware that String splitlines and Bytes don't behave exactly the same (cf here). I guess for an error scenario it's good enough.

[ViBiOh]

Nice catch, beware that String splitlines and Bytes don't behave exactly the same (cf here). I guess for an error scenario it's good enough.